This invention relates to a novel bicycle frame and the method of constructing the bicycle frame.
It is highly desirable to produce a bicycle having a frame that is both rigid and lightweight. Rigidity prevents bending of the frame during cycling. It is desirable to eliminate since bending of the frame because it causes a loss of pedal energy. A lightweight bicycle is highly desirable especially in racing bicycles since less energy is required to propel a lightweight bicycle. The present invention provides a preferred frame and front fork for a bicycle having both low weight and front and rear fork rigidity. This invention is also directed to the method for constructing said bicycle frame and front fork.
This invention is directed to a lightweight rigid bicycle frame comprising left and right subassemblies which are the mirror image of each other; each subassembly has a "C" shaped cross-section; each subassembly has a forward end and a rear end; and the left subassembly is attached to the right subassembly at the forward ends thereof to form the frame having a front section and a rear section comprising:
(a) a head tube; PA1 (b) a crank housing; PA1 (c) a rear fork; PA1 (d) a top hollow member having a front end and a rear end wherein said front end is attached to the head tube; PA1 (e) a down hollow member having a forward and a rear end wherein said forward end is attached to the head tube; and PA1 (f) a seat down hollow member having a top end and a bottom end wherein said top end is attached to the rear end of the top hollow member and the bottom end is attached to the crank housing; the rear section of the frame consisting of the rear end of said left and right subassemblies which are separated from each other to form a cavity to which is inserted and attached a rear subassembly having a "C" shaped cross-section and which is in the shape of an oval folded about its minor axis to form said rear fork of the frame comprising:
(i) two seatstay hollow members each having a forward end and a rear end wherein the forward ends are attached to the top of the seat down hollow member; and PA2 (ii) two chainstay hollow members each having a forward end and a rear end wherein the forward ends are attached to the crank housing and the rear end of one of the chainstay hollow members is attached to the rear end of the other chainstay hollow member.
This invention is further directed to a lightweight front bicycle fork similarly formed from left and right subassemblies attached at the top ends to form a tubular section of the fork which fits into the head tube of the bicycle wherein the bottom portions of the left and right subassemblies form a cavity to which is attached a "U" shaped subassembly. The front fork of this invention is lightweight and rigid.